Replaces the `bun2nix` bun.nix generated file with `mkDerivation` containing
the node modules. This should decrease the nix evaluation time and decrease
the bundle size.
Also switches to [lon](https://github.com/nikstur/lon) instead of npins
for pinning nixpkgs, since it uses the nix library directly instead of
shelling out to `nix-shell` or `nix-build`.
This commit series completes a major infrastructure overhaul:
- Migrate from manual GitHub Actions YAML to nix-actions workflow generation
- Add automated dependency update workflow with scheduled runs
- Add comprehensive Nix package definitions for all components (atlantis, sorcerer, archivist, etc.)
- Create containerized builds with proper Docker support
- Wrap scripts inside nix for better dependency management and shellcheck
The build system now uses pure Nix expressions for both local development
and CI/CD, providing better reproducibility and maintainability.
